Causes of Upper Abdominal Bloating

Upper abdominal bloating has many potential causes.
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Upper abdominal bloating can not only lead to discomfort and gas, but it can significantly interfere with daily activities. There are many potential causes of this symptom, but swallowed air, indigestion and food intolerance are among the most common triggers. Upper abdominal bloating can also be due to a medication side effect -- or related to a more serious health condition. See your doctor for an accurate diagnosis if you have severe or ongoing abdominal bloating.


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Swallowed Air

Bloating is a feeling of increased abdominal pressure. When this symptom occurs in the upper abdomen, it often means something is going on in the stomach or small intestines. Swallowed air is one cause of stomach bloating, and if this is the trigger, belching is often present as well. Eating quickly, drinking carbonated beverages or drinking through a straw can all lead to excess swallowed air. Even poorly fitted dentures or smoking can cause this problem.



Simply eating large meals or fatty foods can lead to a sensation of upper abdominal fullness and bloating, but food intolerance or poor digestion can also cause this symptom. Bloating is common in people who do not properly digest certain types of carbohydrates -- such as lactose in milk, fructose from fruits and vegetables, sugar alcohols commonly found in no-sugar-added foods, or oligosaccharides, found in certain grains, onions, garlic and dried beans, peas and lentils. When these incompletely digested food particles reach the colon, the resident gut bacteria have a feast, and produce excess gas -- which leads to the sensation of bloating. While these symptoms tend to be more common in the lower abdomen, excess gas production can lead to the sensation of bloating throughout the abdomen.



Upper abdominal bloating is also a symptom linked to indigestion, also called dyspepsia. Described as a sensation of pain or discomfort in the upper abdomen, symptoms linked to dyspepsia include upset stomach, gassiness, a sense of fullness or bloating after eating, as well as a gnawing or burning sensation. Dyspepsia is caused by a variety of factors, including medications, delayed stomach emptying, swallowing problems, stomach ulcers or acid reflux.


Bowel Disorders

Abdominal bloating can also be related to a bowel disorder. Irritable bowel syndrome, or IBS, is a collection of symptoms that includes abdominal discomfort, which may be caused by cramping, bloating, diarrhea or constipation. Small intestinal bacterial overgrowth (SIBO), a situation where there is an increase in the amount and type of bacteria that reside in the small bowel, can lead to abdominal discomfort, diarrhea, bloating and excess gas. Long-standing constipation can also lead to a buildup of stool and trapped gas, causing an uncomfortable bloating sensation.

Other gastrointestinal disorders may also lead to abdominal bloating, but the symptoms may not be specific to the upper abdominal area. Celiac disease is an autoimmune condition in which the immune system -- triggered by gluten -- attacks the small intestine. In people with celiac disease, consuming gluten, found naturally in wheat, barley and rye, can lead to bloating, gas and other symptoms. Inflammatory bowel disease, including Crohn disease and ulcerative colitis, and gastroparesis, a disorder that leads to slow stomach emptying, are other conditions that can also lead to bloating.

Other Causes

Other conditions or medications can lead to abdominal bloating, although these may not be specific to the upper abdominal area. Certain medications can lead to dyspepsia or altered movement of the gut muscles, and cause gastrointestinal symptoms which include bloating. Medical conditions which obstruct the outlet between the stomach and small intestines can also lead to bloating, nausea, vomiting and pain. Foodborne illness can cause bloating either while sick or after the active illness has resolved, since food intolerance and IBS can sometimes develop after a foodborne infection. Bloating is a common symptom before and during the menstrual cycle, and can also be a sensation related to fluid retention -- which is a serious issue if caused by liver, kidney, lung or heart disease. Bloating can also be a symptom of certain types of cancers, including cancer of the ovaries, stomach, pancreas and colon.


While some causes of bloating are not serious and can be resolved with changes to diet or eating practices, sometimes bloating is a sign of something more serious. If bloating occurs frequently, or if you experience significant pain, talk to your doctor about your symptoms. Also see your doctor if you have persistent diarrhea, vomiting, blood in the stool, painful or frequent heartburn or unintentional weight loss.

Reviewed by Kay Peck, MPH RD